The present invention relates to data processing and recording and in particular to a method of recording information on a medium in the form of electrical signals.
The use of the prior art methods of providing on a medium a visual presentation of data contained in electrical signals has been generally limited by insufficient speeds of recording information conveyed in the form of electrical signals, low packing density thereof, and absence of reusable media, i.e. media suitable for repeated utilization during recording, readout, and erasure cycles.
There is known a thermochemical method of recording information on a medium in the form of electrical signals. (M. G. Arutjunov, V. D. Markovich. Fast Input-Output of Information, published in 1970, Moscow, Energia Publ., p. 158). It consists in that electrical signals conveying information are converted into thermal signals which affect an information recording medium. With the aforesaid method, the recording medium comprises a paper substrate coated on one side with lead thiosulphate acting as a working layer and covered with a breaching titanium dioxide layer. A powdered aluminum layer is applied to the substrate on the other side.
Black lead sulphide PbS, gaseous sulphur, and sulphur dioxide SO.sub.2 are formed as white lead thiosulphate PbS.sub.2 O.sub.3 is chemically decomposed under the action of thermal signals. Optically nonhomogeneous patterns are thus produced within the working layer of the recording medium to represent the information conveyed in the form of electrical signals. The known method have been open to the objection that the recording of information on a medium is accompanied by the formation of noxious gaseous products, a disadvantage necessitating the use of ventilating facilities. Furthermore, the recording medium utilized in the aforesaid method may not be reused.
Another known method of obtaining and recording information in the form of electrical signals on a medium (A. M. Balbashov. Controlled Transparents on Magnetic Crystals, Kvantovaya Elektronika magazine, 1977, Moscow, vol. 4, No. 9, p. 1933) essentially consists in that a matrix composed of control electrodes is placed in extremely close proximity to a magnetic crystal utilized as a recording medium. The matrix is employed to convert electrical signals conveying the information into corresponding magnetic signals. Magnetic fields set up in the matrix elements under the action of the electrical signals change locally the domain structure of the magnetic crystal. Consequently, a latent image is formed within the magnetic crystal. Limitations inherent in the aforesaid method are the need to make visible the recorded latent image by the use of an additional constructionally intricate optical system comprising a light source, a polarizer, and an analyzer, and also the utilization of a comparatively expensive material (magnetic monocrystal) in the fabrication of the recording medium.
Also known in the art is a method of recording information on a medium in the form of electrical signals, which comprises such steps as application of a vector field and a uniform thermal field to an area within the working layer of the medium wherein the information is recorded, said uniform thermal field being used to heat said area to a temperature above the softening temperature of the binder working layer, in which particles capable of changing spatial attitude thereof in accordance with the recorded information due to a dipole moment are distributed in a uniform manner, the subsequent step being the cooling of said area within the working layer to a temperature below the softening temperature of the binder for fixing the recorded image (cf., for example, U.S. Pat. No. 3,311,903, class 340-174.1).
With such a method, the recording medium must have a constant thickness. The working layer of the medium includes a thermoplastic binder wherein magnetic particles are uniformly distributed. The medium is placed in the vicinity of an electrical-signal-to-magnetic-signal converter. The converter accepts electrical signals conveying information and converts them into magnetic signals affecting a chosen area within the working layer of the medium. In said area the medium particles are magnetized, i.e. the vectors of dipole magnetic moments thereof are oriented in accordance with the magnetic field of the signal being recorded. Following this, the medium is placed in the vicinity of a uniform thermal field source, and said area of its working layer is heated to a temperature above the softening temperature of the binder. As this happens, the viscosity of the binder is appreciably reduced to allow displacement of magnetic particles dispersed therein under the action of ponderomotive forces. The particles are thus grouped with the result that dense and thin formations appear in accordance with the magnetization thereof, induced by a magnetic signal. The thickness of the medium will then change locally, the subsequent step in the aforesaid method being the cooling of the medium for fixing the recorded latent image to a temperature below the softening temperature of the binder.
A disadvantage of the known method is that the recording medium may not be reused.
The aforesaid method has been unsatisfactory due to a complicated and labour-consuming process involved in making visible and reproducing a latent image by the use of a laser beam, utilization of constructionally intricate equipment, and stringent requirements for the thickness of recording media, which are generally limiting factors.